Reroll drive mechanism for graphic meters



Oct. 25, 193,8. D. J. ANGUS REROLL DRIVE MECHANISM FOR GRAPHIC METERSFiled April 6, 1937 ull ATTORNEYS.

Patented Oct. 25, 1938 PATENT oFEicE REROLL DRIVE MECHANISM FOR GRAPHICMETERS Donald J. Angus, Indianapolis, Ind.

Application April 6, 1937, Serial No. 135,264

2 Claims.

It is the object of my invention to provide for graphic meters a re-rolldrive mechanism which not only permits rotation of the re-roll roller inspring-winding Adirection (as in unrolling the record sheet forinspection) without danger of over-,winding the spring and without beinglimited by full winding of the spring, but also without undue shockstops the spring-unwinding movement of the re-roll roller if suchmovement is too rapid, as on breakage of the paper or failure of thesupply of paper.

With that end in view, I provide in the driving mechanism for there-roll roller a slipping clutch which slips upon undue spring-windingmovement of the re-roll roller; and also provide a light-weight memberfrictionally connected with the re-roll roller so that it may slip understress, and provide on that light-weight member a centrifugally operatedpart which cooperates with a stop-pin to stop the light-weight memberand thereby gently stop the re-roll roller Without undue shock upon toorapid spring-unwinding movement of the re-roll roller.

The accompanying drawing illustrates my invention: Fig. 1 is a verticalsection, substantially on the line I-I of Fig. 2, through a drivingmechanism embodying my invention; Fig. 2 isv a fragmentary sideelevation of the mechanism shown in Fig. l, with some parts broken away;and Figs. 3 and 4 are enlarged transverse sections, on the line 3-4 ofFig. 1, through the lightweight, centrifugally operated, frictionallymounted, stopping mechanism, with the centrifugally operated members inits inner and outer positions respectively.

The graphic meter may be of any desired type, in which a record sheetIII or traveling chart is driven at predetermined speed by and over afeed-roll II, from which it passes to a re-roll roller l2 on which it isrewound. The feed-roll l I may be driven in any suitable manner, notinvolved in the present invention; and a graph is made on the record inany suitable manner, well understood.

The re-roll roller I2 is driven by a suitable coil spring I5, shown aswindable by a key on a stem I6, which is held against backward movementby a ratchet mechanism I6'. For such driving, one end of the spring I5is suitably connected to a gear I'I; which is connected through a trainof gears to a shaft I8 carrying and drivingly connected to one end ofthe re-roll roller I2 in any suitable manner. As shown, that drivingtrain includes a pinion I9 meshing with the gear I'I and xed to a gear20, a pinion 2| meshing with the gear 2li and driving a gear 22, and apinion 23 fast on the shaft I8 which drives the re-roll roller I2.

Between the pinion 2| and the gear 22, however, the driving connectionis not positive, but frictional and slippable. To that end, the pinion2| is fast on a shaft 25. Also fast on that shaft 25 is a disk 2S. Thegear 22 is loose on the shaft 25; but it lies in frictional engagementwith the disk 26, into which frictional engagement it is forced by acoiled compression spring 2l lying between the gear 22 and a flange 28of the pinion 2 I. By reason of the frictional engagement between thedisk 26 and the gear 22, relative rotation is permitted between thepinion 2| and the gear 22, as may be required; but the friction issuiciently great so that it is normally adequate for driving the re-rollroller |2.

Loose on the shaft I8 of the re-roll roller is a spool 30, which has africtional engagement on one side with a disk 3| fixed to said shaft I8.A coiled compression spring 32 on the other side of said spool 30, andlying between said spool and the pinion 23, maintains the frictionalengagement between the spool 30 and the disk 3|. The spool 3U is lightin weight, so that when its movement is stopped by the stop shoulder 34its stoppage requires little force.

Within the groove of the spool 3l) is pivoted a stop-member 33, providedwith a stop-shoulder 34 for cooperating with a pin 35 flxedly mounted inthe frame-work of the meter. The stop-member 33, as shown, is of ageneral U-shape (Figs. 3 and 4), with its supporting pivot 33a at thebase of the U and with one arm somewhat heavier than the other so thatthat heavier arm will move outward by centrifugal force if the rotationof the spool 30 is too rapid. That heavier arm, which is thus thrownoutward by centrifugal force, is the one which carries the stop-shoulder34.

In order to avoid the necessity for any spring for normally holding thestop member 33 retracted within the groove of the spool 30, the pin 35is preferably located so that it will not be engaged by thestop-shoulder 34 if in the course of slow rotation of the spool 30 theheavier arm of the stop-member 33 drops out of the spoolgroove bygravity. To that end, the stop-pin 35 is desirably located, asillustrated in Figs. 3 and 4, slightly above the horizontal plane of theshaft |8 on that side of the spool 3|) which travels downward in thenormal spring-driven movement of the re-roll roller I2.

In operation:

The spring I5 is Wound in the usual manner, by a key on the stem I6.

The spring I5 drives the re-roll roller I2 through the interveninggearing; which driving occurs with no normal slipping between the gear22 and the disk 26.

If with the spring I5 wound or nearly wound the operator winds there-rcll roller I2 backward, as by unrolling the re-rolled record chartto see what its showing was at some earlier time or over some earlierperiod, and thus moves the gear I'I backward to cause winding of thespring I5, no breakage occurs when and if the spring I5 reaches fullywound condition, because such slipping then occurs between the gear 22and the disk 26 as may be necessary to accommodate the excess movementof the re-roll roller I2 after the Spring I5 is fully wound.

If for any reason the re-roll roller I2 starts to rotate forward toorapidly, or in the spring-unwinding direction, as because the recordsheet breaks or the supply of record sheet is exhausted or the operatorsuddenly releases the unrolled record sheet, the excessive speed ofrotation causes the heavier arm of the U-shaped stopmember to ilyoutward so that the stop-shoulder 34 will strike the pin 35. This stopsthe spool 3U abruptly. But the hammer-blow between the stop-shoulder 34and the pin 35 is relatively light, because the frictional mounting ofthe spool 30 on the shaft I8 permits such shaft I8 and the re-rollroller and the parts geared thereto to be brought to a relatively gentlestop by reason of the slipping, usually for only a part of a revolution,between the spool 30 and the disk 3I. Thus the re-roll roller I2 isprevented from running away in the event it somehow gets free, but themechanism is nevertheless guarded against undue shock.

I claim as my invention:

1. In a graphic meter, the combination of a re-roll roller, a drivingspring therefor, a driving connection interconnecting said drivingspring and said re-roll roller, a light-weight rotatable memberfrictionally interconnected with said reroll roller and provided with acentrifugally actuated part having a stop-shoulder, and a stoppin in aposition to be engaged by said stopshoulder on centrifugal actuation ofsaid centrifugally actuated part to stop said light-weight member andthereby after some slipping at the frictional connection between saidlight-weight member and the re-roll roller to cause a gentle stopping ofthe latter.

2. In a graphic meter, the combination of a re-rcll roller, a drivingspring therefor, a driving connection interconnecting said drivingspring and said re-roll roller, a light-weight rotatable memberfrictionally interconnected with said reroll roller and provided with acentrifugally actuated part having a stop-shoulder, a stop-pin in aposition to be engaged by said stop-shoulder on centrifugal actuation ofsaid centrifugally actuated part to stop said light-weight member andthereby after some slipping at the rctional connection between saidlight-weight member and the re-roll roller to cause a gentle stopping ofthe latter, said driving connection between the reroll roller and thespring including a frictional drive which permits slipping on reversewinding of the re-roll roller with the spring wound.

DONALD J. ANGUS.

